CALYPTOCRINID^. 335 



Remarhs. — Eucalypiocrinus was originally described by Goldfuss as hav- 

 ing no stem; and Phillips, who discovered another species with the stem 

 attached, proposed for this the genus Hypanthocrinus. Angelin and Zittel, 

 who accepted Phillips' genus, describe its base as less deeply funnel-shaped, 

 the anal tube as extending beyond the tips of the arms, and the partition 

 walls enclosing the arms as being constructed principally of one piece. 

 Neither one of these characters is constant, and we cannot regard the two 

 forms as distinct generically. That the anal tube rises above the arms is of 

 very little structural value, if we admit that the neck-like prolongation 

 from the disk represents a part of that tube. The earlier writers describe 

 the radials as basals. Koemer discovered the true base in 1843, but he 

 supposed it was quinque-partite, and so did de Koninck and Le Hon. Hall in 

 1863 found that it consisted of but four plates, and this was confirmed by 

 subsequent authors. 



Eucali/ptocrinus is a most perplexing genus, owing to the peculiar struc- 

 ture of its ventral part, which was apparently not correctly understood by 

 Hall. He described the partition walls as interbrachials -, while in fact they are 

 not separate plates, but the outer processes from the plates of the disk and 

 tube, respectively, a sort of compound structure for which we adopt the name 

 " partition walls." The twenty plates forming the lower ring of the disk we 

 regard as large interambulacral plates meeting over the ambulacra ; but as 

 to the relations of the plates of the second ring we are somewhat in doubt. 

 We have suggested in Eevision, Part III, p. 132, that they probably repre- 

 sented four of the orals, and that the fifth was pushed upward, and consti- 

 tutes a part of the anal tube. This seems not improbable if we consider that 

 the posterior oral in all Palaaozoic Crinoids is pushed more or less out of 

 place by the anus ; and it may be expected that this was the case to a high 

 degree in a genus in which the anal tube is large and strictly central. 



Miller's Eucalyiotocrimis dliptims is too young a specimen to determine its 

 specific relations. A similar specimen from Rochester, N. Y., is figured by us 

 on Plate LXXXIII., Fig. 7. 



Eucalyptocrinus tennessece, E. PUlUpsi, E. conicus, E. nashvillce, E. exfensus, 

 E. gibtosus, E. Icevis, and E. Goldfussi, all of Troost, are mere catalogue names. 

 E. armosus McChesney is a jSiphonocrinus, and E. eornutus, E. excavatus, 

 both described by Hall, and E. ramifer of Roemer, have been referred by us 

 to Gallicrinus. 



